Engineered by Alfred P. Boller, the 145th Street Bridge (1910) employed a more modest design than the Macombs Dam Bridge (1895). This 1999 photo was taken from the Bronx shoreline. (Photo by Kevin Walsh, www.forgotten-ny.com.)

FILLING THE GAP AT 145th STREET: In 1895, the New York State Legislature enacted a law providing for the construction of a new Harlem River bridge between 145th Street in Manhattan and 149th Street in the Bronx. Two business leaders, Fordham Morris and John de la Vergne, spearheaded the drive for the 145th Street Bridge, which was to not only connect growing residential neighborhoods in Harlem with new industrial areas in the South Bronx, but also fill in a one-mile gap between river crossings. The legislation read as follows:

The bridge is to be completed within twelve years; to be not more that 70 feet nor less that 60 feet wide; to be 24 feet high in clear above high water of spring tides, with two contiguous draws which with the center pier; shall be not less that 240 feet; and have clear water ways no less than 100 feet. The cost of construction not to exceed $1,250,000, with such further sums as may be required for damages from change of grade and for purchase of land and cost of condemnation.The specifications met the new navigation requirements for the Harlem River ship channel, which opened in 1895. The new channel provided for the first time a navigable waterway between the East River and the Hudson River. During this time, many of the existing Harlem River bridges had to be rebuilt to meet the new navigation requirements.

Preliminary surveys were undertaken by the New York City Parks Department, but at the beginning of 1898, this responsibility was transferred to the newly created Department of Bridges. Before this transfer took place, both the Army Corps of Engineers and the New York City Board of Estimate approved plans for the new bridge.

Alfred P. Boller, whose design credits include the Madison Avenue, Macombs Dam and University Heights swing bridges, was selected by the new Department of Bridges to design the new 145th Street crossing. William H. Burr was appointed the consulting engineer. The new entity also let out the initial construction contract to O'Brien, Sheehan and McBean at a low bid of $1 million.

REVISING PLANS: On the basis of the operation of the Macombs Dam Bridge, whose 1895 design would be copied for the 145th Street Bridge, several design changes were made as follows:

The length of the draw span was reduced from 400 feet to 300 feet.

The width of the bridge was increased from 70 feet to 90 feet, permitting the installation of a wider roadway.

Steel and reinforced concrete was to be used instead of masonry (and earthen fill) on the approaches. (Compared with other Harlem River swing bridges, the 145th Street used fewer materials.)

Excessive ornamentation on the 145th Street Bridge was to be avoided. The revised bridge was to utilize a more modest design.

The machinery was to utilize electric power rather than steam power.

The Secretary of War approved the new 145th Street Bridge plans in 1900. Subsequently, the New York City Board of Estimate approved the revised project. These alterations added to the cost of the bridge, and it soon became evident that the $1.25 million allowed by the 1895 legislation would be insufficient to pay the entire cost. At the request of city officials, the New York State Legislature allocated additional funds for construction and right-of-way acquisition.

Work on the 145th Street Bridge began on April 19, 1901. Construction of the bridge was delayed by the simultaneous construction of the IRT subway tunnel, which ran under the southern pier where a working shaft was located. The $2.75 million bridge opened to traffic on August 24, 1905.

DESIGN AND CONSTRUCTION: The 145th Street Bridge, a rim-bearing swing bridge, is comprised of three trusses supported by a drum girder at the center pivot pier, and by toggle end lifts on the approach piers. A 368-ton turntable powers the central 1,177-ton swing span. The floor system at the level of the bottom chords provides for two 27-foot wide roadways between each exterior truss and the central truss. There are also two 9-foot-wide sidewalks along the exterior trusses.

The drive motors, brakes and other machinery for rotating the swing span are located on the movable span, within the space between the roadway deck and the circular drum girder. The control desk and electrical controls for the swing span are located in this room, from which the swing span is operated.

Sharon Reier, author of The Bridges of New York, described the 145th Street span as follows:

The 145th Street Bridge attempts to recapture the grace and originality of the Macombs Dam Bridge, but it is an uninspired copy, even if the designer was the same. When a design achieves a certain quality, the lack of challenge in repeating it can give its double a humdrum appearance, which is probably what happened with the 145th Street Bridge. It is, however, a pleasant enough bridge with its green-tiled gazebos.

CONNECTING TO THE STREET GRID: The 145th Street Bridge provides two lanes of eastbound and two lanes of westbound traffic between Manhattan and the Bronx. In Manhattan, the bridge connects to the corner of 145th Street and Lenox Avenue, and in the Bronx, the bridge connects to 149th Street and River Avenue. Until 1972, the bridge also carried the NY 22 designation.

The Manhattan approach was rebuilt in 1957 to carry traffic over the Harlem River Drive. Motorists must use side streets in order to connect to the parkway. The Bronx approach, which connects to the Bronx street grid and the Major Deegan Expressway (I-87), was rebuilt in 1990 to replace the original Bronx flanking span.

REBUILDING THE 145th STREET BRIDGE: In July 2004, the NYCDOT began to rebuild the 145th Street Bridge. The $85 million project, which included the complete replacement of the swing span and approach spans, reconstruction of substructures and seismic retrofitting, was comprised four stages and progressed as follows:

March-October 2006: partial closure of bridge and approaches

November 2006-February 2007: full closure of bridge and approaches; removal of old swing span removal and placement of new swing span

March-June 2007: partial closure of bridge and approaches

July-September 2007: miscellaneous work

Two lanes of the new bridge were opened to traffic on June 16, 2007, and the remaining two lanes opened that September. The new bridge has four standard-width (12-foot-wide) lanes--two in each direction--but no longer has a center median.

According to the New York City Department of Transportation (NYCDOT), which owns and maintains the 145th Street Bridge, the span carries approximately 30,000 vehicles per day (AADT).

This 2009 photo shows the new 145th Street Bridge, which opened two years earlier. (Photo by Kevin Walsh, www.forgotten-ny.com.)

Type of bridge:Construction started:Opened to traffic:New span opened to traffic:Length of main span:Length of two channels:Total length of bridge and approaches:Width of bridge:Width of roadway:Number of traffic lanes:Clearance at center above mean high water:Steel used in structure:Masonry used in structure:Foundation type:Cost of original structure:Cost of new structure:

SOURCES:The Bridges of New York by Sharon Reier, Quadrant Press (1977); "A Guide to Civil Engineering Projects in and Around New York City," American Society of Civil Engineers (1997); "145th Street Bridge To Close For Four Months," NY1 News (10/28/2006); "New York City Department of Transportation; Kevin Walsh.